CMS - Trigger RECFA-Meeting Leopold-Franzens-Universität Innsbruck, 26 March 2004 Presented by...
Transcript of CMS - Trigger RECFA-Meeting Leopold-Franzens-Universität Innsbruck, 26 March 2004 Presented by...
CMS - TriggerCMS - Trigger
RECFA-MeetingLeopold-Franzens-Universität
Innsbruck, 26 March 2004
Presented by
Claudia-Elisabeth WulzClaudia-Elisabeth WulzInstitute for High Energy Physics, Vienna
http://wwwhephy.oeaw.ac.at/p3w/cms/trigger
C. - E. Wulz 3 RECFA, March 2004
Cross sections for different processes vary by many orders of magnitude
• inelastic: 109 Hz• W l: 100 Hz• tt: 10 Hz• Higgs (100 GeV): 0.1 Hz• Higgs (600 GeV): 0.01 Hz
Required selectivity 1 : 10 10 - 11
TriggerTrigger
-
Cross Sections and Rates
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Only calorimeters and muon system involvedOnly calorimeters and muon system involvedReason: no complex pattern recognition as in tracker required (appr. 1000 tracks at 1034 cm-2s-1 luminosity), lower data volumeTrigger is based on:Trigger is based on:Cluster search in the calorimetersTrack search in muon system
CMS Level-1 Trigger
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Level-1 Trigger and Institute Responsibility4
0 M
Hz
pip
elin
e,
late
ncy
< 3
.2
s
HFHF HCALHCAL ECALECAL RPCRPC CSCCSC DTDT
PatternPatternComparatorComparator
Trigger Trigger
RegionalRegionalCalorimeterCalorimeter
TriggerTrigger
4 4 4 4 4+4 4+4
4 4 (with MIP/ISO bits)(with MIP/ISO bits)
MIP+MIP+ISO bitsISO bits
e, J, Ee, J, ETT, H, HTT, E, ETTmissmiss
Calorimeter TriggerCalorimeter Trigger Muon TriggerMuon Trigger
Responsibility
of Vienna Institutemax. 100 kHz L1 Accept
Global TriggerGlobal Trigger
Global Muon TriggerGlobal Muon Trigger
GlobalGlobalCalorimeterCalorimeter
TriggerTrigger
Local Local DT TriggerDT Trigger
Local Local CSC TriggerCSC Trigger
DT TrackDT TrackFinderFinder
CSC TrackCSC TrackFinderFinder
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System Overview
Global Trigger + Global Muon Trigger: 1 Rack
Drift Tube Track Finder: 3 Racks
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Muon Trigger Detectors
Drift Tube Chambers and Cathode Strip Chambers are used for precision measurements and for triggering.
Resistive Plate Chambers (RPC’s) are dedicated trigger chambers.
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Barrel Muon Chambers
Mounting of a Drift Tube Chamber into the iron yoke
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Transport of the First Magnet Coil Module
A good muon trigger needs a high magnetic field!
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Regional Muon Trigger
Track Finder Processor• Pipeline logic running at 40MHz (LHC bunch crossing frequency)• Implemented in programmable logic devices• Based on extrapolation and pattern matching methods
Drift Tubes(CSC’s similar)
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Drift Tube Trigger Track Finder
The trigger is based on correlating compatible track segments pointing The trigger is based on correlating compatible track segments pointing to the vertex. At most four detector planes are used in to the vertex. At most four detector planes are used in azimuth (transverse to the magnetic field direction) and three in (transverse to the magnetic field direction) and three in pseudorapidity (along the beam axis). If possible, track candidates found in both (along the beam axis). If possible, track candidates found in both projections are then matched.projections are then matched.
Eta Track Finder
Track segment (with direction of extrapolation)
Phi Track Finder(Sector Processor)
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Muon Trigger PrototypesSector Processor Timing Module
Eta Track Finder
Wedge Sorter (Bologna)
Trigger Crate
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Global Muon Trigger
Output:Output:8 bit8 bit, 6 bit , 6 bit , 5 bit p, 5 bit pTT, ,
2 bits charge/synch, 3 bit 2 bits charge/synch, 3 bit quality,quality, MIP bit, Isolation bitMIP bit, Isolation bit
Output:Output:8 bit8 bit, 6 bit , 6 bit , 5 bit p, 5 bit pTT, ,
2 bits charge/synch, 3 bit 2 bits charge/synch, 3 bit quality,quality, MIP bit, Isolation bitMIP bit, Isolation bit
Inputs:Inputs:8 bit 8 bit , 6 bit , 6 bit , 5 bit p, 5 bit pTT, ,
2 bits charge, 3 bit quality,2 bits charge, 3 bit quality,1 bit halo/eta fine-coarse1 bit halo/eta fine-coarse
Inputs:Inputs:8 bit 8 bit , 6 bit , 6 bit , 5 bit p, 5 bit pTT, ,
2 bits charge, 3 bit quality,2 bits charge, 3 bit quality,1 bit halo/eta fine-coarse1 bit halo/eta fine-coarse
Best 4 Best 4
4 4 RPC RPC barrelbarrel
4 4 DT DT
4 4 CSC CSC
4 4 RPC RPC forw.forw.
252 MIP bits252 Quiet bits
DR/CSC/RPC: DR/CSC/RPC: combined in combined in Global Muon Trigger, Global Muon Trigger, isolation and MIP isolation and MIP information addedinformation added
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Global Muon Trigger Efficiencies
Sophisticated, flexible algorithm using geometry and quality to achieve:• good efficiency • reasonable rates• ghost suppression
DTCSCRPCGMT smart
GMT ORGMT ANDGMT smart
Muon Trigger Efficiency
GMT Efficiency
Optimal combinationOptimal combinationhigh efficiency, small ratehigh efficiency, small rate
2.087.4AND
2.997.3SMART
5.498.1OR
Rate
kHz
for 14
GeV
GMT Option
Rates for L=2x1033 cm-2s-1
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Hadron Calorimeter
The Global Muon Trigger adds information to muon candidates by correlating them with calorimeter regions. It confirms muon candidates with MIP information and determines their isolation.
Barrel Hadron Calorimeter Forward Hadron Calorimeter
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Global TriggerThe trigger decisiontrigger decision may be based on simple or more complex criteria, similar to data analysis:
• Logic combinations of trigger objects sent by the Global Calorimeter Trigger and the Global Muon Trigger Best 4 isolated electrons/photons ET, , Best 4 non-isolated electrons/photons ET, , Best 4 jets in forward regions ET, , Best 4 jets in central region ET, , Best 4 -Jets ET, , Total ET ET
Total ET of all jets above threshold HT
Missing ET ETmissing, (ET
missing) 12 jet multiplicities Njets (different ET thresholds and -regions) Best 4 muons pT, charge, , , quality, MIP, isolation
• Thresholds (pT, ET, NJets)
• Optional topological and other conditions (geometry, isolation, charge, quality)
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Global Trigger Algorithms
Logical CombinationsObject Conditions
128 flexible algorithms running in parallel are implemented in programmable logic devices. The trigger decision (Level-1-Accept) is a function of the 128 trigger algorithm bits (for physics). 64 more technical algorithms are possible.
eis.(1)
eis.(2)
ET(1) > ET(1)threshold
ET(2) > ET(2)threshold
0o ≤ φ()<360o
0o≤φ()<360o
70o≤φ()-φ()<90o
+(1)
μ-(2)
pT(1) > pT(1)threshold
pT(2) > pT(2)threshold
0o ≤ φ(1) < 360o
0o ≤ φ(2) < 360o
170o ≤ |φ(1) - φ(2)| < 190o
ISO(1) = 1, ISO(2) = 1MIP(1) = 1, MIP(2) = 1SGN (1) = 1, SGN(2) = -1
ETmissing
OR
Particle Condition formissing ET
Particle Conditions for muons
Particle Conditions for isolated electrons
ET(eis.) > ET(eis.)threshold pT(μ) > pT(μ)thresholdET
missing > ETthreshold
OR
ALGORITHM AND-OR
ANDAND
eis .
ETmiss ing
eis . μ
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Global Trigger Boards
Every 25 ns the Global Trigger takes the decision to reject an event or to make it available to the High Level Trigger for further consideration. It consists of the following electronics boards:
PSB (Pipelined Synchronizing Buffer) Synchronization of inputs (7 modules)GTL (Global Trigger Logic) Logic (1-2 modules)FDL (Final Decision Logic) Trigger decision (1 module)TCS (Trigger Control System Module) Central trigger control (1 module)L1A (Level-1 Accept Module) Distribution of trigger decision (1 module)TIM (Timing Board) Timing (1 module)GTFE (Global Trigger Frontend) Readout (1 module)
PSB (Pipelined Synchronizing Buffer) GTL (Global Trigger Logic)
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Trigger Control System and Timing
Trigger Control System Module Timing Module
The TCS Module controls the data taking based on fast status signals sent by the subsystems. The Timing Module is used for the distribution of the LHC clock.
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Physics, Software, Management
– Trigger studies (Level-1, High Level Trigger)– Software for testing and operation of the trigger hardware– Coordination of the complete level-1 trigger software– Software for the reconstruction of muons
– Preparations for physics analysis, especially with studies in the field of Supersymmetry
– Membership in CMS Management Board– Membership in Editorial Boards for Trigger and Physics Reconstruction and Selection
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Summary
The CMS-Trigger Group of the The CMS-Trigger Group of the Vienna Institute for High Vienna Institute for High Energy PhysicsEnergy Physics is responsible for the Level-1 is responsible for the Level-1 Drift Tube Drift Tube Track Finder,Track Finder, the the Global Muon TriggerGlobal Muon Trigger and the and the Global Global TriggerTrigger and is developing software for triggering. It is and is developing software for triggering. It is working on the working on the reconstruction of muonsreconstruction of muons and is and is performing studies for performing studies for physics analysis,physics analysis, in the field of in the field of supersymmetry.supersymmetry.
The current group members are:The current group members are:Scientists (physics, electronics, computer science):Scientists (physics, electronics, computer science):J. Erö, M. Jeitler, A. Nentchev, J. Erö, M. Jeitler, A. Nentchev, N. Neumeister, P. Porth, N. Neumeister, P. Porth, H. Rohringer, H. Sakulin, H. Rohringer, H. Sakulin, J. Strauss, A. Taurok, C.-E. WulzJ. Strauss, A. Taurok, C.-E. WulzTechnicians:Technicians:H. Bergauer, Ch. Deldicque, H. Bergauer, Ch. Deldicque, K. Kastner, M. PadrtaK. Kastner, M. PadrtaStudents:Students:M. Galánthay, S. Kostner, B. Neuherz M. Galánthay, S. Kostner, B. Neuherz